package client

import (
	"bytes"
	"code.google.com/p/gorilla/rpc"
	"code.google.com/p/gorilla/rpc/json"
	"io"
	"net/http"
)

type Codec interface {
	ContentType() string
	EncodeRequest(method string, args interface{}) ([]byte, error)
	DecodeResponse(r io.Reader, reply interface{}) error
}

type jsonCodec struct{}

func (jsonCodec) EncodeRequest(method string, args interface{}) ([]byte, error) {
	return json.EncodeClientRequest(method, args)
}

func (jsonCodec) DecodeResponse(r io.Reader, reply interface{}) error {
	return json.DecodeClientResponse(r, reply)
}

func (jsonCodec) ContentType() string {
	return "application/json"
}

var JsonCodec Codec = jsonCodec{}

type Client struct {
	path   string
	codec  Codec
	client *http.Client
}

func NewClient(path string, client *http.Client, codec Codec) *Client {
	return &Client{
		path:   path,
		codec:  codec,
		client: client,
	}
}

func (c *Client) Call(method string, args interface{}, reply interface{}) (err error) {
	buf, err := c.codec.EncodeRequest(method, args)
	if err != nil {
		return
	}
	body := bytes.NewReader(buf)
	req, err := http.NewRequest("POST", c.path, body)
	if err != nil {
		return
	}
	req.Header.Set("Content-Type", c.codec.ContentType())

	resp, err := c.client.Do(req)
	if err != nil {
		return
	}
	defer resp.Body.Close()

	err = c.codec.DecodeResponse(resp.Body, reply)
	return
}